If you already know why getting an instruction manual is a dam fine idea, you can skip the video spiel and go straight to the calculate below and input your sizes. If not, maybe watch the video first.
If you haven’t already seen an aquarium assembled in five minutes (without the braces at that point) see this You Tube clip.
If you don’t have your final measurements yet, you can put in some approximates to get your critical data, like the approx weight, floor pressure etc